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Query: UMLS:C0699790 (colon cancer)
 28,837 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Of 111 carcinomas developing in 73 patients with ulcerative colitis, 46 (41.5%) arose in the rectum where they are directly accessible to sigmoidoscopy. Fifty-eight per cent of single carcinomas developed in the rectum. The extent and frequency of rectal dysplasia was assessed by examining slides of rectal mucosa with an eyepiece micrometer. Slides from 46 patients with carcinoma and 22 patients with dysplasia but no carcinoma in whom proctectomy or proctocolectomy had been carried out were examined by this method. Thirteen of 15 patients with carcinoma of the colon (87%) and 21/22 patients (95%) with large bowel dysplasia showed evidence only of rectal dysplasia. However, there was marked variability in the proportion of dysplastic rectal mucosa even in those patients with rectal carcinoma, while in some patients dysplasia was limited to a small focus. Because of the possibility of false negative biopsies due to sampling error, multiple biopsies should be taken to detect dysplasia. Their state should be recorded and deliberately varied at subsequent visits. Careful sigmoidoscopy and multiple biopsies in this study had potential value as an aid in the detection of 85-90% of all carcinomas. In practice the figure would almost certainly be lower due to intrinsic bias (see discussion) so that, although regular sigmoidoscopy and biopsy would be of great value when colonoscopy is not available, the latter should be included in any long-term programme of carcinoma prevention.
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PMID:Value of sigmoidoscopy and biopsy in detection of carcinoma and premalignant change in ulcerative colitis. 48 53

Prior studies confirm the increased incidence of carcinoma of the colon in chronic ulcerative colitis. The authors reviewed clinical and histologic data retrospectively in 23 patients with colon carcinoma and chronic ulcerative colitis. Twenty-two of these patients had dysplasia of colonic epithelium remote from the cancer. The authors prospectively reviewed clinical data and rectal and colonoscopic biopsy specimens on 36 patients with chronic ulcerative colitis, 12 with Crohn's colitis, and 12 with miscellaneous disorders. Eight patients with chronic ulcerative colitis had dysplasia; 6 have had colectomy, and 2 of these had carcinoma. No patient without chronic ulcerative colitis had dysplasia. Patients with chronic ulcerative colitis should have periodic rectal and colonoscopic biopsies, and those with moderate to marked dysplasia require colectomy because of the increased risk of colon carcinoma.
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PMID:Malignant potential of chronic ulcerative colitis. Preliminary report. 75 30

We report on an 80-year-old female patient with a villous polyp of the bladder. We believe this lesion may correspond to an intermediate stage in the well known sequence of injury-metaplasia-dysplasia-carcinoma of the large intestine. Intestinal metaplasia in the bladder is a potentially malignant lesion. If villous adenomas are diagnosed early, before malignant transformation, simple excision can achieve cure.
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PMID:[Villous adenoma of urinary bladder. Report of a new case]. 129 32

Aberrant crypts are recognized in methylene blue-stained, unsectioned, colonic mucosa by their increased size, elliptical lumenal opening, thicker epithelial layer, and increased pericryptal region. Aberrant crypt foci in rodents are observed as early as 2 weeks and for at least 9 months after a single dose of carcinogen, have a distribution that parallels that of tumors, and have an increased number of aberrant crypts per focus with time after the carcinogen dose. The ability to quantify these lesions in the entire colon of rodents in less than an hour suggests that aberrant crypts may provide a highly efficient in vivo bioassay for colon carcinogens. Since aberrant crypt foci appear to be the earliest identifiable putative precursors of colon cancer, they represent lesions that can be characterized further for the earliest genetic and biochemical alterations. In F344 rats, we have demonstrated that aberrant crypts have multiple histochemically-detectable enzyme alterations. Using similar techniques, we were the first to demonstrate aberrant crypts in unsectioned human mucosa. After embedding and sectioning, these microscopic aberrant crypts resemble rare lesions described earlier in the literature after extensive serial sectioning. In rats and humans, aberrant crypts may be histologically normal or display varying degrees of dysplasia and histochemically-detectable altered enzyme activities. These putative, preneoplastic lesions should reveal early changes that precede colon cancer and ways to alter their progression.
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PMID:Aberrant crypts in human colonic mucosa: putative preneoplastic lesions. 136 89

Single and multiple colonic crypts exhibiting dysplasia that are detectable in situ by staining of rat colon with methylene blue are called aberrant crypts (AC) and may serve as an intermediate marker for colon cancer. In a characterization study, we have established the kinetics of AC growth and development over a period of 20 d following injection of rats with the carcinogen azoxymethane (AOM). AC are not present at 5 d post-injection, but are a constant feature at 10 d and thereafter. Multiple AC, presumably clonal, begin to evolve at 10 d and are consistent by 20 d, forming incipient microadenomata. We have examined 20 candidate chemopreventive agents for inhibition of AC. All agents were given in AIN-76 diet, at two dose levels, with injections of AOM. AC were measured after 5 weeks of growth. Among the most active AC-inhibiting agents were BHA, DFMO, quercetin, diallyl sulfide, 18 beta-glycyrrhetinic acid, and ascorbyl palmitate. In a post-initiation study, the differentiating agent sodium butyrate was ineffective, but piroxicam was highly effective in modulating AC growth. Further, piroxicam inhibited AC development at all stages of growth from single to polycryptal clusters of AC. The AC assay shows marked sensitivity and specificity for screening agents for chemoprevention of colon cancer.
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PMID:Growth kinetics and chemoprevention of aberrant crypts in the rat colon. 146 5

Experimental studies have allowed the identification of foci of aberrant crypts on the fixed methylene-blue-stained mucosal surface of rodent colons after colon carcinogens administration. Similar lesions can also be observed and quantified on the mucosal surface of the human colon, using the same technique. Several foci showed dysplasia at histological examination, thus allowing the identification of microadenomas. Microadenoma may thus be a precursor lesion of adenomas and colorectal cancer. The identification of aberrant crypt foci and microadenomas in vivo could provide a new end-point for studies on the effect of environmental and genetic factors in the early stages of cancer of the large intestine. Further studies are needed to define the natural history of these lesions. Moreover, a critical evaluation of current colon cancer prevention strategies should be considered.
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PMID:Early events in human colorectal carcinogenesis. Aberrant crypts and microadenoma. 148 80

Surgical specimens from 2 patients with chronic ulcerative colitis accompanied with colon cancer were evaluated by immunoperoxidative staining using monoclonal antibodies A7 (against human colon cancer), S202 (against human gastric cancer), and anti-carcinoembryonic antigen (CEA). The three monoclonal antibodies were reactive with cancerous tissue, anti-CEA antibody and monoclonal antibody S202 reacted with dysplasia tissues, whereas monoclonal antibody A7 did not. Using high-iron diamine technique for mucosubstances (sialomucin and sulfomucin), cancer and dysplasia showed no secretory elements. Surrounding mucosa showed both sialomucin and sulfomucin secretion.
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PMID:[Two cases of ulcerative colitis with colon cancer: immunoperoxidase staining using monoclonal antibodies against gastrointestinal tumor and mucin staining]. 169 18

Aberrant crypt foci (ACF) can be observed and quantified on the mucosal surface of formalin-fixed human colon resections after staining with methylene blue. To determine whether these ACF could be identified in fresh tissue, 10 colon resections were collected after surgery for colorectal cancer. Unfixed and fixed flat normal colonic mucosa from each colon were scored for ACF under a dissecting microscope after methylene blue staining. The number of ACF per cm2 and the average number of crypts per foci correlated highly in unfixed and fixed mucosa (r = 0.93 and 0.78, respectively). A significantly higher frequency of lesions was found in left-sided compared to right-sided colon resections. To determine whether the topographic features of the ACF gave an indication of the histological appearance, 68 specimens containing ACF or normal mucosa were examined histologically. The presence of slit-like lumen in the crypts of ACF on the mucosal surface correlated with the presence of dysplasia at histology, thus identifying microadenomas. These two observations suggest that the topographic classification of ACF in vivo could be used to distinguish microadenomas, a putative precursor lesion of colon cancer.
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PMID:Classification of aberrant crypt foci and microadenomas in human colon. 184 71

Laser excitation of hematoporphyrin derivatives (HPD) localizing in tumors of the tracheobronchial tree and bladder is useful in the identification and treatment of those tumors. A comparable utility for HPD in the endoscopic localization of colonic tumors may be possible. In this study the ability of HPD to identify 1,2 dimethylhydrazine (DMH) induced colon cancer in rats is evaluated. A total of 111 rats were studied with HPD. Sixty-nine rats received weekly injections of DMH (20 mg/kg) and 42 received injections of the vehicle alone. Twenty-four hours after the intravenous injection of 5 mg/kg of HPD, 18 DMH-induced tumors were identified by visual fluorescence using excitation by either a blue light (390-436 nm) or an argon laser (488 and 514 nm). This represented 100% of the visually or microscopically detected tumors. Seventy-five fluorescent areas were noted that did not contain evidence of cancer. The majority (63) of false positive areas contained lymphoid follicles. All but 2 false positive areas (73/75, 97%, p less than .001) were seen in DMH-treated animals, suggesting that they were an artifact of DMH treatment. HPD fluorescence did not identify microscopic dysplasia. We conclude that HPD fluorescence is an effective method of identifying early colonic cancer and may have a potential clinical role in patients at high risk for colorectal cancer.
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PMID:Fluorescence localization of early colonic cancer in the rat by hematoporphyrin derivative. 186 65

The main objective of the present study was to sequentially analyze growth and morphological characteristics of aberrant crypt foci (ACF) in the rat colon. Sprague-Dawley rats were given a single injection of a carcinogenic dose of 1,2-dimethylhydrazine-HCl and at varying time points ranging from 2 to 57 weeks, groups of 5 rats were terminated. The number and crypt multiplicity of ACF were determined in the distal 8 cm of the colon. In addition, ACF were processed for histology and then graded for the presence of nuclear atypia using a score of 0-4. The findings of the present study demonstrated that ACF exhibit the characteristics expected for precursor lesions. ACF were present at all time intervals in large numbers in the colons of rats treated with 1,2-dimethylhydrazine-HCl and were present when adenocarcinomas were observed. The number of ACF with 4 or more crypts and those exhibiting a higher grade (grade 4) of nuclear atypia increased significantly at or beyond 19 weeks. These features of ACF, particularly the presence of nuclear atypia indicative of dysplasia, provide strong support for the hypothesis that ACF are precursor lesions of chemically induced colon cancer.
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PMID:Sequential analyses of the growth and morphological characteristics of aberrant crypt foci: putative preneoplastic lesions. 191 50


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